It is one of the biggest prizes for achievement on earth – $5m over 10 years and $200,000 per year for life thereafter – awarded to an African head of state or government who has served his constitutionally allowed term. Donated by the Sudanese telecoms billionaire Mo Ibrahim, the prize, now in its third year, has celebrated the achievements of the Mozambiquan peacemaker Joaquim Chissano and the Botswanan statesman Festus Mogae. And this year, it will not be awarded. The prize committee, on which Ibrahim does not sit, declared that it could not select a winner from a field that included Nigeria's former president Olusegan Obasanjo, Thabo Mbeki of South Africa and the favourite, John Kufuor of Ghana.

The prize committee surprised us, but in hindsight it would have been premature to reward Ghana's former president without a better understanding of his longer-term economic legacy. Rather than despairing of the plight of African governance, we should be heartened by the decision not to award Kufuor the prize, not because he was explicitly a failure, but because in thinking he automatically deserves it we have once again fallen victim to low expectations and judged him on an archaic understanding of what constitutes African leadership.

Ghana, running as it is a large fiscal deficit, is not as well placed as the continent's other emerging economic powers to weather the global downturn. Ghana and its leadership have to be judged alongside Botswana and Zambia, both of which have recently gone through relatively transparent and peaceful elections, and both of which have suffered from the collapse in demand for their primary commodity exports. Both, too, have been able to leverage their sound macroeconomic management during the boom years to secure international financing to bridge the gap left by the fall in commodity revenue in this slump. Ghana's economy has not demonstrated such strength. Accra's strategy of waiting for its newly discovered oil reserves to start generating revenue has been proved deficient.

A peaceful and democratic transition of power is laudable, yes, but it is the bare minimum to be expected of a government. The tragic failure of countries such as Guinea is not a yardstick by which to measure Ghana, or indeed any of the other nations and leaders on the continent. Africa's progressives have suffered long enough from unwarranted associations with their dictatorial predecessors, and to reward them for simply not backsliding is patronising. I hope that the Mo Ibrahim prize committee's decision is reflective of this: it is supposed to be a prize for excellence, not adequacy.

Of course, the concern is that this will undermine the already fragile confidence that many observers have in the continent, which has long suffered from a disconnect between perception and reality and a persistent underestimation of its improvements in governance and economic growth over the last decade. While the prize is awarded by a distinguished panel who no doubt have an insight into the contemporary state of Africa, the news of their decision is released into a public domain that is not so privileged, one that is spoonfed a diet of negatives. That darker side of the continent no doubt needs a light shone in on it, but not without the balance and objectivity afforded to other regions of the world, else "Africa" in the popular imagination will remain conflated with Guinea, and men like Moussa Dadis Camara, rather than with visionaries like Ibrahim.

This is a deficiency in us, the media, but it is one that Ibrahim and his foundation must wrestle with if they want to avoid this decision becoming one more reference in the thesis, still being written, that post-colonial Africa's future is a continuance of the unfulfilled potential that has been its historical burden.